1. Technical Field
The invention relates to air springs and in particular to an air spring in which the end plate which is mounted opposite of the piston is formed integrally as a onepiece plastic member combining the end plate with a mounting bracket which is hollow to form an auxiliary fluid chamber. More particularly, the invention relates to such a combination end plate and mounting bracket which is mounted to a supporting structure which is oriented perpendicular to the direction of orientation of the corresponding structure on which the piston is mounted.
2. Background Information
Air actuators and in particular air springs, consist of a pair of spaced end members and an intervening flexible sleeve or bellows formed of an elastomeric material to form an internal pressurized fluid chamber. These devices are used for many applications. One main application is between spaced components of a vehicle for absorbing road shock or supporting parts of machinery and equipment on which shock forces are continually imparted, and for regulating and maintaining the spacing between the two spaced components of various pieces of equipment including vehicles. These air springs usually consist of an upper end member or end plate which is usually attached to the underside of a bracket or support member, and an opposite piston member which is usually mounted to the top surface of a second supporting structure spaced from the first supporting structure. Examples of such air springs and their manner of attachment to spaced structures are shown in U.S. Pat. Nos. 4,564,177; 4,832,317; 4,787,606 and 5,32,139. Other types of air springs are incorporated with a pneumatic or hydraulic damper such as shown in U.S. Pat. Nos. 4,796,870; 4,934,667 and 5,180,145.
However, all of these known prior art air springs and air springs/strut combinations are mounted between two structures having generally parallel aligned surfaces. However, for some applications, it has been found desirable to mount one of the end members, and in particular the top end plate, to a structure such as the sidewall of a chassis frame, which extends perpendicularly to the mounting surface of the opposite structural member on which the piston is mounted. Likewise, it has become desirable to increase the internal volume of the fluid chamber without substantially increasing the size or limiting the stroke of the air spring.
U.S. Pat. No. 5,326,082 shows one type of air spring in which an auxiliary chamber is formed within the interior of the piston member as well as within the interior of the end cap or end member, both of which are formed of a plastic material to reduce corrosion and facilitate the production of the end members. However, again in this air spring structure, the mounting surfaces are parallel to each other and no structure is provided for securing one of the end members, and in particular the end member opposite of the piston, to a mounting surface perpendicular to that of the piston mounting surface.
The present invention provides an air spring having an integral one-piece end plate and mounting bracket combination for attaching one end of the air spring to a supporting structure.
The combination end plate mounting bracket of the invention comprises an annular end plate formed with a semi-circular wall and a corresponding semi-circular opening, which opening provides fluid communication between the main internal pressure chamber of the flexible sleeve and the auxiliary pressure chamber formed in the bracket. The bracket extends outwardly from the end plate so that the auxiliary fluid chamber is above the end plate.
The mounting bracket and end plate of the invention are formed of a high-strength plastic material which is free from corrosion and can be manufactured relatively easy with a minimum of manufacturing steps. The bracket has an upstanding wall with a generally planar face perpendicular to the semi-circular wall of the end plate for mounting the air spring on a complementary L-shaped member such as the side rail of a vehicle chassis. A half dome-shaped upstanding wall forms the auxiliary fluid chamber with the upstanding planar wall.
Another aspect of the invention preferably provides mounting the end plate and bracket to the open end of an air spring opposite of the air spring piston with the upstanding wall of the bracket being generally perpendicular to the mounting surface on which the piston is adapted to be mounted.
A further aspect of the invention preferably includes providing a plurality of reinforcing ribs extending along the inner and outer surfaces of the upstanding planar wall of the bracket and along the inner surface of a half dome-shaped enclosure wall within the auxiliary fluid chamber, and along the top and bottom surfaces of portions of the end plate wall to form an extremely rigid and strong structure.
A feature of the invention is the providing of a rigid conduit integral with the planar front wall of the bracket which extends perpendicularly outwardly therefrom for subsequent attachment to a remote supply of a pressurized fluid, such as air, into the auxiliary and main fluid chambers of the air spring.
Another feature of the invention is minimizing the number of parts heretofore required for the air spring and providing the end plate with a stepped outer annular flange for attachment of the open end of the flexible sleeve thereto, preferably by a pressure clamp or similar sealing member.
The foregoing advantages, construction and operation of the present invention will become more readily apparent from the following description and accompanying drawings.